1. Field of the Invention
This invention relates to a bicycle, and more particularly to a bicycle accessory device that includes an accessory (such as a tail lamp, a mudguard, or a rear carrier rack), a clamp, and a fastening unit cooperating with the clamp to lock the accessory on a bicycle frame.
2. Description of the Related Art
Referring to FIG. 1, a tail lamp 111 is mounted on a seat tube 11 by a clamp 112. Referring to FIG. 2, a mudguard 121 is mounted on a seat tube 12 by a clamp 122. When either of the clamps 112, 122 is loosened slightly from the seat tube 11, 12 after a period of use, a corresponding one of the tail lamp 111 and the mudguard 121 moves or pivots relative to the seat tube 11, 12.
Referring to FIG. 3, a rear carrier rack 131 is mounted on a bicycle frame 13 by two lock bolts 132. When the rear carrier rack 131 is assembled to the seat tube 13, damage may be caused to the outer surface of the seat tube 13 by the lock bolts 132, thereby affecting adversely the appearance of the seat tube 13.